1. Field of Invention
The present invention relates to an electro-optical device, such as a liquid crystal display device. The present invention also relates to a transverse electric field mode liquid crystal display device.
2. Description of Related Art
In related art TN (Twisted Nematic) mode liquid crystal display devices, alignment of liquid crystal molecules is controlled by sealing liquid crystal between two transparent substrates and applying an electric field in a vertical direction to the substrate via a transparent electrode provided on each of the substrates. Related art document Japanese Unexamined Patent Application Publication No. 2000-162602 discloses that an electric field is applied to liquid crystal in a nearly parallel direction to the substrate. This is referred to as a transverse electric field mode or an IPS (In-Plane Switching) mode.
In the related art liquid crystal display device, a TFT (Thin Film Transistor) driving method in which a thin film transistor is used as a switching element is adopted. However, since, in order to form a TFT element, it is necessary to perform exposure, development and etching processes in a number of times, the manufacturing process becomes complicated to consequently increase the manufacturing cost.
Also, in related art vertical electric field driving mode liquid crystal panel, the related art includes a signal voltage generated by pulse-width-modulation or voltage-modulation based on display data. However, display quality deteriorates because of the occurrence of transverse irregularity or vertical crosstalk on display image. Related art documents Japanese Unexamined Patent Application Publication No. 2003-87734 and Japanese Unexamined Patent Application Publication No. 11-337980 suggest that a shield structure be provided between pixel electrodes of a liquid crystal panel. However, such a shield structure results in a decreasing aperture ratio.